The Department of Defense model development arose from the experience of the US Nay Medical Department as described in another Section of this Segment of the Website. The experience described there of the US Navy Medical Officers, which had stimuli originating back to the World War II, Korean and Southeast Asia conflicts in which the various Service Medical Departments participated, had a positive impetus on them that resulted from the achievements of the nearby MGH model development combined with the perceived needs of each Service for both support of field medical care and care of service personnel and their families during all phases of military service. In addition to the US Navy project, each service had projects directed at functional areas which needed support from information technology. In 1974 these separate efforts were organized within the Department of Defense into a "Tri-Service Medical Information System" (TRIMIS) Project structure which coordinated the various Military Service efforts and also organized an approach to the procurement of a unified information architecture to be eventually used by all of these services. A competitive demonstration process was established in the 1980’s to select a common architecture and implementation components to be used in configuring systems for various fixed and deployable facilities. There was background recognition of the backup role of the VA facilities in the event of various conflict contingencies but the VA effort remained largely independent during this period and until very recently. It was the interest of the Military Services, and the military service experience of many trauma care physicians - particularly Surgeons, that stimulated the application of information technology to civilian trauma care and to regional trauma care systems. This was a significant contribution of this model development.

The competitive development of candidates for a unified architecture, particularly targeted to fixed definitive care facilities, by 1987 led to the selection of an architecture which had been adapted from the VA DHCP architecture by one supplier and for which there was by that time considerable experience. The candidate selected was named "Composite Health Care System (CHCS)" and a staged procurement was undertaken to introduce it into all of the service’s fixed facilities. During 1996 a configuration was also deployed in the aircraft carrier George Washington (CVN 73).